In general, a column spacer used in a color filter of a display device is manufactured using a negative photoresist.
Furthermore, it was confirmed via tests that after coating PR in a thickness of 2.2 μm, the height of 2.2 μm remained when exposed using a photomask with a transmittance of 100%, the height of about 1.8 μm when exposed using a photomask with a transmittance of 10%, the height of about 1.6 μm remained when exposed using a photomask with a transmittance of 5% and the height of 0 μm remained when exposed using a photomask with a transmittance of 0%. That is, in order to produce a shape having four steps in total through one exposure, other areas having four transmissivities are required.
However, when the difference in the transmittances of the photomask for each area is not large, there is a problem that even if four tones are used, no PR pattern is made according to the pattern shape of the photomask, and as the tones of the photomask increase, there is a problem that the production cost increases.